Add new SliderValue GUI widget

Signed-off-by: Vojtech Bocek <vbocek@gmail.com>

Change-Id: Ic5d44314f501341140dd7059d1cb753341f5844c
diff --git a/gui/pages.cpp b/gui/pages.cpp
index bf44b38..11fe9b0 100644
--- a/gui/pages.cpp
+++ b/gui/pages.cpp
@@ -273,6 +273,12 @@
             mRenders.push_back(element);
             mActions.push_back(element);
         }
+		else if (type == "slidervalue")
+		{
+			GUISliderValue *element = new GUISliderValue(child);
+			mRenders.push_back(element);
+			mActions.push_back(element);
+		}
 		else if (type == "listbox")
 		{
 			GUIListBox* element = new GUIListBox(child);